294 



smaller spines, doubtless the incipient stage of the next new ray. The sharp 

 points of the rays may project as much as 2 mm., and give the pinnules a sjjiny 

 margin. 



The pinnules present all grades from narrow scalpel-shaped forms to almost 

 fan-shaped types. 



The polyps are numerous and are confined to the margin of the pinnules. 

 These meet and overlap on the meta-rachidial surface, except in the oldest 

 specimen where there is a free space on the lower half. 



The colour varies in the three types ; the smallest (C) is light brown, the 

 next (B) is considerably darker with bluish spots studded over it, while the 

 largest (A) is very pale brown with purple patches, especially on the pro-rachidial 

 surface. This difference in colour may be due to the preservation. 



Locality ; Andamans. 



Previously recorded from Gulf of Suez. 



Pteroeides andamanense, n. sp. Plate VI. fig. 6. 



A single specimen of a yellowish colour represents this new species. 

 Total length of colony . 

 Length of rachis .... 

 Breadth of rachis .... 

 Length of stalk .... 

 Thickness of stalk .... 

 Number of pinnules 

 Number of rays .... 

 Length of pro-rachidial margin of largest pinnule 

 Breadth of insertion of largest pinnule 

 Breadth of largest pinnule 

 Distance between pinnules 



The whole colony is very much flattened in one plane. 



The zooid-plate is median, and there is no cushion at the pro-rachidial 

 insertion of the pinnule, so that the species falls into the pellucidum-group. 

 The stalk and keel are tough, and the former tapers gently to a point where it 

 is slightly incurved. The pinnules are thin and the pro-rachidial insertion is 

 higher than the meta-rachidial. They are developed laterally and do not meet 

 on the meta-rachidial surface except for a short space at the upper end. No 

 pinnules are developed at the extreme tip of the rachis. Between the meta- 

 rachidial insertion and the keel there are a number of small projecting spines, 

 generally three to five. The rays are eight to ten in number and are composed 

 of two to four spines which project in some cases 2 to 3 mm. They are large 

 and conspicuous. There are no small needles in the zooid region. 



